Machine-switching selector-switch



Nov. 8, 192 7.

F. A. STEARN MACHINE SWITCHING SELECTOR SWITCH CIRCUIT Filed y 1924 :5 sheets-sheet l //7 van for flaw/Q7 A; jfearn Nov. 8, 1927.

F. A. STEARN MACHINE SWITCHING SELECTOR SWITCH CIRCUIT 3 Sheets-Sheet 2 Filed July 1, 1924 o o o o s o o o 0c arms N mQ

Nov. 8, 1927.,

- F. A. STEARN MACHINE SWITCHING SELECTOR'SWITCH CIRCUIT s Sheets-Sht 5 Filed July 1, 1924 Patented Nov. 8, 1927.

hearse rarest caries.

FRANKLIN A. STEARN, 0F PATERSON, HEY i7 JERSEY, ASSIGLIORFTO EVESTERN ELEG- YORK.

a CORPGIt-ATION on new MACHINE-SWI'ECHING SELECTOR-SVIITCH CERCUI'I.

Application filed July 1,

This invention relates to a telephone exchange system, and more particularly to the control and operation of selector switches in p a machine switching system. i

It 15 an ObJQCl] of this lnvention to provide an improved method of operating selector switches.

In machine switching ofiices common senders are provlded having registers which are positioned by dial interruptions transmitted sequence, a so-called sequence switch is associated with each selector. The sequence switch is provided with a number of contact closing cams, and during the operation of a selector switch moves through a plurality of positions to variously close its cam contacts. Its movement and the operation of apparatus for its control occupies an appreciable amount of time for each selector switch associated in sequence to complete a call from one subscriber to another. For this reason it is desirable to combine operating functions to limit the apparatus of a selector switch and the number of cam eontacts on its associated sequence switchand the amount of time required in selecting the talking conductors.

A feature of this invention is in the provision of means in a sender and selector switch whereby group selection and trunk hunting may be made by a combined single function of the selector switch.

A. further 'l'eature 01"" this invention is in the provision oi means whereby banks of terminals associated with selector switches.

"of each bank.

This and other features sit the invent 1924. Serial 1%. mane.

will be apparent from the following description takenin connection with the accompanying drawings.

lVhile the invention hasbeen disclosed as particularly adapted for use with selector switches in panel type machine switching ofiices, it is apparent, from the following description that the invention has a wider utility and that by slight modification it could be adapted for other types of switches.

Referring to the drawings, Figs. 1 to 8 and Fl 1 inclusive, when arranged in the order illustrated by the diagram in Fig. 4, disclose in detail the circuits and apparatus of a panel type machine switching system embodying the principles of the present invention for combining the group selection and trunk hunting intoone function in the operation of a selector switch.

Fig. 1 illustrates a subscribers station K, a line ircuit and a line switch. Theline switch is of the type well-knownin the art for selecting an idle district selector switch.

Fig. 1 illustrates the sender in diagrammatic fornn embodying the principles of the present invention arranged to control a selector switch in such manner that the group selection and trunk hunting is made in a single upward movement of the selector switch brushes.

Fig. 2 illustrates a district selector switch for selecting an idle sender and for selecting an idle oilice selector switch. as directed by the sender.

Fig. 3 illustrates an ethos selector switch embodying the principle of the invention to combine the group selection and trunk hunting; into a single operating function.

The subscribers station, line switch and district selector switch are the same as described in detail in Patent No. 1,505,171. issued to the applicant August 19, 1924. sender used to control the selector switch is the same as described in detail in my abovementioned patent with the modification shown in Fig. 1 for controlling the office selector switch (Fig. 3).

General description.

A. subscriber initiates a call by al the receiver from i y e I in This operation causes The I Ill) to operate and line switch 100 to rotate tor the selection of an idle district selector switch, illustrated in Fig. Upon the selection of the idle district selector tl e lino switch is arrested in its forward movement and the apparatus ot the district selector is operated to sel-ct an idle sender. The apparatus of the sender is then positioned by the operation ot the dial in accordance with the ollice code and number of the wanted subscribers line. lhe interruptions from the dial position the registers not shown) in the sender to control so ector switches. Each selector switch is directed by the sender for brish and group selection, and each switch in the train except the last then hunts for an idle trunk or line associated with the next selector switch to he used in the train of switches for the association 015 the calling subscriher with a particular otlice and with a particular line in said particular oll'ice. lhc est selector switch in this train ot switches is the sender to a particular line. Is switch is not pertinent to the invention and is not shown. The district selector switch shown in Fig. 2 is operated in the manner described in Patent No. 1.505.17l, issued to the applicant August 19. 1924;, and does not incorporate the combined group selection and trunk hunting feature o't this invention. This feature however, may be applied to this type of selector switch as well as the selector switch shown in Fig. 0.

Assuming that the di switch (Fig. has selected an idle sender and has been directed by said sender to associate a set of its brushes with condu 3123, Zilland of the oilice selector swrfzch 3), the apparatus ot the sender is operatcl to direct the selector switch 3) for brush selection which positioi'is the brush set 3230 upon the first set of terminals of its associated bank 34 0. Upon the completion o't' brush selection. the hrushes $331.. and are brought into engaaen'ient with the first terminals of bank old and a circuit is completed from the grounded U ciated with said lirs set at terminals to the stepping relay ot the sender. Let it he as sumed that the sender positix group selection and that hrush set otlice selector is then driven in ca ipwaro movement. Each association of sleeve brush with the lirs" iinal in group oil bank 8&0 operates the stepping relay 15? in the sender. lhe operation and release ot the stepping relay establishes circu to operate the counting relays of the sender. l/Vhen a number at counting relays have been operated in accordance with the position of a particular sender the O lavs and relay 151 the sender iaaaaon ot the up-drive 330 of the and 0 counting re operated. The operation of maintains the ener magnet in the ottice selector switch i 4 to continue the iiipward i'i'ioi'en'icnt ct brush member 330 un il. idle terminals to a succeedii'ig selector switch have been selected.

it is a parent from the above description that no sc a 'ate operating; :t'unction is necessary in the oiiice selector switch 3) to initiat and control. the trunl: hunting function o t said selecti'ir switch. it will he turlher noted that no commutator is used during group selection and trunk hunting with 'ihc cziiceptir'r-n of a centering coininutathr 342 which has a segn'ient for each terminal. li hcu a couunutator common to a plurality ct hanks is used tor group selection. it is usually IIQCGSSZH'Y to sub-dividc all banks un l'ia'nilv into groups. With the (.rrangd mentshown in Fig. 3, the hanks may be subdivided. llll') groups each g .up to include any nuui ier o5 terminals \vithinthe liinits ot the haul; and the groupinc' in each of a plu- 2 z 'iilhfi in a itranic he dillierent.

'il e adi'a itage in the use oi? this arrangement is that any number of trunks within the limits of a bank, extending to a particu he ollice may he connected to terminals of the haul: to term one of the groups in the bank I [Jo/cited description.

Let it he assiuned that the calling subscriher l5 desires to establish a connection with a suliiscrihefs line. The calling: suhscruier upon initiiuing a call removes the receiver 'troin the switchhoolc. This opcration establishes a circuit to operate line re av 'lOl from grounded battery through the if winding: of relay i l]. the innermost l; c' contact ot cuto'l? relay 102. line conil 1 t E03 through the suh ,.l:tion apparati o 5 line and thenc over line conductor and releases to advance the brushes of the switch to the second lei-n'iinals or" the respective hanks with which they are associated. The sccoi'id ter minal a socia ed with lin'ush 10 1; is conne ted to g ound and magnet 'lilfi (Again operates to advance the brushes to th s; seto't l ;fll'll iials lcadiiuz' to the first of the group (it trunks connected to district selector itches such as shown in Fig. 2.

It the first trunk of the ground potential is associa Wu. brush 10S and its associated contact ai continues to step until an is ii'ound. .i-t

s luu vv =le trunlr is cha eas es ner contacts of relay 226, test conductor 114C,

brush 108 and its associated contact, conductor 107, the left contact and left winding of relay 1.01,, conductor 115 to ground through both windings of relay 102. Relay 102 is operated inthe circuit traced to open the energizing circuit for magnet 105 and to extend the line conductors to the district selector switch, Fig. 2. lay 102 further establishes a circuit through its intermediate contact to energize sleeve relay 226. This circuit may be traced from grounded battery through the left winding of relay 226, left nornial contact of relay 227, right lower contact of cam 203, sleeve conductor 118, brush 109 and its associated contact, winding of message register 119. conductor 120, the intermediate contact of relay 102 to groundthrough the upper winding of relay 102.

Upon the energization of sleeve relay 226, a circuit is established to operate relay 228, which circuit extends fro-m grounded battery through the right winding of this relay, upper contacts of cam 20 1, right contact of relay 226, and thence to ground through the right upper contact of cam 205. At its left inner contact, relay 226 connects ground potential, to the test conductor 11 1 of the selected trunk to mark the trunk busy to other line switches. The locking circuit for line relay 101 is opened at the left inner contact of relay 226 to cause its release. The energization of relay 228 establishes a circuit to rotate sequence switch 200 out of position 1.. Thi. circuit extends from grounded battery through the magnet winding, lower right hand contact of cam 206, right inner contact of relay 228 to ground at the right upper contact of cum 207. The sequence switch is thus rotated from position 1. to position 2 in which position, an operating circuit is established for relay 227 from grounded battery through its left winding to ground through the left upper contact of cam 205. The operation of relay 227 closes a locking circuit for relay 226. extending through the "left hand winding'of relay 226, the left contact; relay 227. thence to the sleeve conductor 118 over the right upper contact of cam 203. Upon reaching position 2. the sequence switch connects a new holding ground to the test conductor 11 1 at the left lower contact of earn 205. This holding circuit is maintained until the district sequence switch is restored to normal.

When the district sequence switch reaches position 1%, a circuit is established to operate stepping magnet 229 cf the sender is established from.

The operation of refinder switch. This circuit may be traced from grounded battery through the contact and winding of magnet 229, left lower con tact of cam 208, right inner contact of relay 228 to ground through the right contact of cani 207. A circuit is further established at this time through the winding of magnet 229, windings of relay 230 and 2 1 1 in parallel and thence to ground at the left upper contact of earn 209. Relays 230 and 2 1 1 do not energizev since their windings are shunted by the ground connected through the armature of relay 228.

lVhcn the sequence switch 200 rotates out of position 1, the initial energizing circuit for relay .228 is opened at the upper cont-acts of cam 20 1, but this relay remains locked over a circuit extending from grounded battery through its left winding, its left contact, the lower right contact of cam 210, lower left contact of cam 211, left outer contact of relay 226, brush 231 and its associated contact to ground on terminals associated with the brush extending to busy senders. llilagnet 229 is energized under the control of i tate the brush assembly until an idle sender is found. An idle sender is characterized by the absence of ground on the terminal associated with brush 231. lVhen a terminal of this character is encountered, the holding circuit for relay 228 is opened and it thereupon deenergizes. The release of relay 228 opens at its right inner contact, the energizing circuit for stepping magnet 229 to arrest the rotary movement of the brush assembly. The release of relay 228 further establishes a circuit to energize sequence switch magnet 200, to rotate the sequence switch from position 2 to position 3. This circuit may be traced from grounded battery through the magnet winding, left upper contact of cam 206, right inner contact of relay 228, to ground through the right contact of cam 207. lhe release of relay 228 removes the shunt from around the windings of relays 230 and 21st and the energizing circuit previously traced through their windings is now effective. The current through the winding of magnet 229 in this circuit is not of suffi cient strength to cause its operation. The operation of relay 230 prepares circuit paths between the district selector switch and the selected idle sender and associates a ground with brush 231 to operate apparatus of the self-interrupting contact to re sender to prepare it to receive dial interates the dial to produce circuit il'ltCll'LlPtlOliS in accordance with the oliicc code and num ber the wanted subscribers line designation. The interriu tions from the dial open the circuit extending: to the over conductors and leftcontacts of relay 230, brushes 236 and 24:5 and their associated contacts over which the registers of the sender are set to record the digits of the wanted line designation.

W hen th egis c the sender have been setthe district sele is con trolled by the sender code registers in such manner that one of its movable brush sets is directed to an idle trun elect tch suc 'intioiu by and group selection the mail ner r Patent l lo. 1,505,1'? assumed that follov A district selector SWiGCl] i 2 is i main in this posi tl sor Hull

switch n as .hown the district selecto sender for i a i d trunk hunting; in

therefore he cttina of {deuce switch tion durinq' the siin sender controls 1e succecdin51 si'vitcus the train. Upon tie association of th trict selector switch with conductors l and 353. a circuit is estahlishee' to 0]" ..o W relay 31.3, from grounder. battery through its right wii'idiue' lower contacts of cain conductor 313 terminal 257, hrush 25E icit upper and right lower contacts oi cam 220 right outer contatt of rela, 230. brush 23? 5 and its associated contact, lower contact of cam 155, rightnorinal contact relay 151, winding; of stepping); relay 304:, condim" 157, and thence over th fundamental shown in my aforementioned patent. returning over conductor 1536, lower contact of cam 154i. brush 263 and its associated contact. left contact of relay 2414;, rurht lower and left up per contacts of cam 219, hrush terminal 256. conductor 31% to around rough the left upper and lower contacts of cam 302.

The operation of relay 315 ostahlishes circuit to energize sequence switch ma from grounded hattery throu left contact of cam 3ll. to the left contact of relay switch is thus rotated from position 1 to poion 52. During the rotation of the secuence ch. the enei'ii' path for relay .pened but a lockin circuit is established i iom grounded battery throuo' 'i its rip; t hiding, contacts of cam 303, ri ;ht inner con: tact of relay 315, left upper contact of earn 3 ,3, thence over the fundamental to grount through the left contacts of earn 302. l i ith the sequence switch 300 in position 2, a circuit is established to energize up-drive magnet 321 from grounded battery through its winding. right upper contact of cam 3ll to groundthrough the left contact of relay 315. e movable brush shaft is driven pward 0i id throu l v o c tor 3%- i l 1 contacts cam 304 to a junct:'' the fun amental circuit to c of the sender stepping redine of the relay 315 in a iner. Upon the completion lection. the fundamental circuit is .'.h sender by the operation of the inn relays and relay in the otlice (or switch is released The release of relay arrests the upward movement of the brush shaft and brush 3415, since the entor updriye magnet 321 is couta ct. The release of rehlishes a circuit to enerct 300 from grounded battery winding, left contact of cam 310 d through the left back contact of The energization of magnet 300 1c sequence switch from position 2 to position 3.

il hen hrush selection is completed the sender rotates its sequence switch into .'.ion 10 in which position office group ection and trunlr hunting take place. The undo-menta circuit is now e tablished in a l =i manner than the fundamental deict brush and {group select on and office hrush selection. Upon the rotation of the sender sequence switch into pouit is estahlishcd to operate ,iition 10, a cir d through the lower contact of cam no lieu; of the fundamental circuit exom roundcd hattery through the relay 315, left contacts of 334 COiKll' 31 i. terminal 256. brush left upper and rio ht lower contacts of 219, left contact of relay 24 i, hrush 2G3 and its associated contact lower contact of cam 154- to e'roni'id through the ontact of re- A second established as a part of the fundamental circuit from ground through the winding; of the sender stepping relay right normal contact of relay 151, lower Contact of cain hrush 237 and its associated contact right outer contact of relay 230, right lower and left upper contacts of cam 220, brush 259. terminal 5257. conductor 313, upper contacts of cam 308, brush 331. terminal 334.. resistance 350 to erounded battery. ihis latter circuit is established as soon as hrusl es 331, and 333 have been. associated with the first of tori" llifi the bank which takes place upon a subsequent upward movementot' the brushes after the completion of brush selection and the energization of trip magnet 322. The circuit toenergize the trip magnet may be traced from grounded battery through the winding of this magnet to ground through the right lower contact of cam 309. The stepping relay 1 52 and the oiiice circuit relay 315 are operated when each of the parallel paths of the fundamental circuits are established in positions 3 and 4 respectively of sequence switch 300.

.The operation of relay 315 establishes a circuit to rotate the sequence switch 300 from position 3 to position 1. The circuit for energizing the sequence switch magnet may be traced from grounded battery through its winding, left upper contact of cam 311, to ground through. left contact of relay 315.

Relay 315 is maintained operated in this position of the sequence switch over the fundamental circuit previously traced.

Bank 3 10. is shown divided into groups 01. equal numbers of terminals. The bank may, however, be subdivided into groups to include any number of terminals within the limits of the bank. A plurality of such banks are ordinarily associated with each selector switch and each bank may be subdivided into groups with diilerent numbers of terminals in the groups of each bank. Grounded battery through resistance 350 .is connected to the first test terminal of each group or a terminal separating groups. Each time that brush 331 is engaged with a terminal. connected to resistance 350 and battery poten tial, a circuit is established to operate the stepping relay 152 in the sender. When brush 331 disengages a terminal connected to resistance 350, the stepping relay 152 .releases. The operation and release of relay 152 operates counting relays in the sender to count the number of groups over which brush set 330 progresses. It will be noted that conductors 360, 361 and 362 are con nectcd to terminals in the third group.

In sequenceswitch position 1, a circuit is established to energize the up-drive magnet 321 from grounded battery through the winding of this magnet, right upper contact 01? cam 311, to ground through the left contact of relay 315. Upon the energization of nuignet 321, the brush set 330 is moved up ward and the brushes 331, 332. and 333 brought into engagement with the bank terminals. It being assumed that a trunk terminating inthe third group of bank 340 is to be selected the code registers of the sender will have been set to associate the #2 counting relay 158 with the contact of relay 152. The initial operation of the stepping relay 152 operates counting relay 158. The operation of counting relay 158 establishes a locking circuit for itself and an operating circuit for counting the No. 2 counting relay, which is eflectlve upon the release of stepping relay 152. On further upward,

counting relays No. 1, No. 1, N0. 0, No. 0'.

and relay 151 in a manner described for the operation for counting relays No. 2 and No. 2. Relay 151 in attracting its right armature opens the fundamental circuit extending through the winding of stepping relay 152 and in attracting its, left armature opens the energizing circuit for relay 1'50 and establishes a holding circuit for relay 150 over the fundamental circuit This holding circuit may be traced from grounded battery through the winding of relay 150, left alternate contact of relay 151, upper contact of cam 155, brush 237 and its associated contact, right outer contact of relay 230, right lowerand left upper contacts of cam 220, brush 259, terminal 257, conductor 313, upper contacts of cam 308, brush 331, to the test ter minals oi the third group of bank 340. A busy trunk toa succeeding selector switch is characterized by ground associated with the sleeve conductor. Assuming that the first and second trunks of the group are busy, relay 150 is maintained in an operatedposition during the upward movement of the brush set 330 over these terminals. The con-. tinued energization of relay 150 maintains a circuit through its contact for holding relay 315 operated and the continued energiza tron oi? relay 315 maintalns the energizing path for the up-drive magnet 321. Assummg that the third terminals of the group,

337, 333 and 339 are associated with an idle selectorswitch terminal 337 is not characterized by a busy ground and the holding circuit for relay 150 is opened to cause its re lease. The release of relay 150 opens the holding circuit for relay 315 and the release of relay 315 opens the energizing circuit for the up-drive magnet 321, thus arresting the upward movement of brush set 330. It

will be noted that a circuit is established in position a of the sequence switch, Figure 3 from grounded battery through the left winding of relay 315, right contacts of cam:

lit)

switch 300 may be traced from grounded battery through its winding, left lower con tact of cam 310 to ground on the left normal contact of relay 315. The sequence switch magnet is now energized thr ugh master contact 301 to rotate the sequence switch into position 7. in position 7, a circuit is established to operate relay 315 :trom grounded battery through its left winding to ground through the lower contacts of cam 302. The operation of relay 315 establishes a circuit to energize magnet 300 to rotate the sequence switch into position 8. This energizing circuit may be traced from grounded battery through the winding of magnet 300, left upper contact of cam 311, to ground through the lett contact of relay 315. Upon the rotation of the sequence switch into position 8, the energizing circuit for relay 315 is opened to cause its release. In position 8 ol the sei'gnence switch, the trunk conductors 318 and Bi l; are connected through cams 305 and see and brushes 3233 and 332 with terminals 338 and 339 and conductors 360 and extendiz. to a subsequent selector switch to be positioned by the sender for completing the connection to a wanted subscriber.

The selector switches controlled by the sender to complete the telephone connection to the wanted subscribefis line and the release of the selector switches upon the termination of the use ot the talking conductors by the subscriber: is the same as described in my aforementioned copending application.

From the foregoing description it wil] be apparent that the combined features of group selection and trunk hunting as applied to selector switches may be utilized to economize in apparatus a d the t me necessary to complete teleph connections between subscribers and to pc 'mit more [lexible grouping of trunl-zs in the switch banks.

What is claimed 1. ltn an automatic telephone exchange system, in combination, a selector switch having a lllOiillJle brush set, a relay operative to control the lllOVOll'lCUl; of said brush set, a bank of fixed trunk terminals divided into groups, a sender, means in said sender to maintain said relay operated during a continuous movement of said brush set to select a particular group and an idle trunk in said group, and means associated with a terminal of each group to control said sender.

2. In an automatic telephone exchange system, in combination, a selector switch having a movable brush set and a bank of fixed trunk terminals divided into groups, a sender, means to establish a revertive con trol of said switch by said sender, and means to control said brush set in a continuous movement to select a particular group and an idle trunk in said group by the said revertive control exercised by said switch over said sender.

3. In an automatic telephone exchange system, in combination, a selector switch having a bank out lined terminal sets and a set of brushes for cooperationtherewith, said sets of terminals being divided into groups, a control relay and operating magnet for said switch, said magnet being under the control of said relay for advancing said brush set in group and terminal hunting movements, a sender, a stepping relay for said sender, two control circuits extending from said switch to said sender, means in said sender for maintaining the operation of said control relay over one of said circuits continuously during the group and hunting movements of said brush set, means operative during the group selection movement ol said switch over said other control circuit for intermittently operating said stepping relay, and means in said sender operative upon the termination of group solection and the engagement of said brush set with an idle terminal set for opening both of said control circuits.

in a telephone system, a selector switch having a movable brush set, a bank of lined trunk terminals divided into group), a sender, means in said sender to cause coin tinuous movement of said brush set to select a pa 'ticular group and an idle set of ter minals in said group, and means a.-..sociated with a terminal of each group to control said sender.

5. a telephone system, a selector switch having a movable brush set, a bank of lixed trunk terminals divided into groups, it sender, means to operate said brush set under control of the sender to select a group of terminals, and means in the sender responsive to a condition on the terminals of the selected group to cause the brush set to continue its movement without interruption to select a set of terminals in the group.

6. In a telephone system, a selector switch having a movable brush set, a bank of fixed trunk terminals divided into groups, :1. sender, means to operate said brush set under control of the sender to select a group of terminals, and means in the sender responsive to a fined condition on the first set of terminals in each group and to the busy condition on succeeding terminals to cause the continuous movement of said brush set.

In witness whereof, hereunto subscribe my name this Q lth day oi June A. ll, 192i.

FRANV 

